It has been found desirable to treat gas and waste water from vinylidene halide polymerization processes in order to reduce and preferably to eliminate release of vinylidene halide monomers to the environment. Use of carbon black for absorption of residual vinylidene halide monomers may require expensive handling and regeneration of the carbon black. A new, simple process is desired for destroying residual vinylidene halide monomers in gas and waste water process streams without producing dangerous by-products.